>>12543857I'm pretty sure the first emission line known was hydrogen alpha (Balmer alpha). The photosphere imprints a huge absorbtion line at Halpha on the blackbody spectrum coming from below. The chromosphere above however emits halpha, and so can be viewed with a telescope. The halpha emission from the chromosphere can be seen sometimes in eclipses, as a pinkish colour.
Beyond that a lot of emission lines exist in the ultraviolet, which was only accessible after the space age.
